Steam-boiler



(N0 Model.)

G. L. ALLEN. STEAM BOILER.

No. 478,677. Patented July 12, 1892.

4 WL Z UNITED STATES PATENT OFFICE.

GEORGE L. ALLEN, OF WVORCESTER, MASSACHUSETTS.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 478,677, dated July 12,1892. Application filed February 1'7, 1892. Serial No. 421,887. (Nomodel.)

To aZZ whom it ntcty concern:

. Be it known that I, GEORGE L. ALLEN, a citizen ot' the United States,residing at )Vorcester, in the county of WVorcester and State ofMassachusettshave invented a new and useful Steam-Boiler, of which thefollowing, together with the accompanyingdrawings, is a specificationsufiiciently full, clear, and exact to enable persons skilled in the artto which this invention appertains to make and use the same.

My present invention relates to that class of steam-boilers in which theupper and under parts of the shell are both upwardly arched, ofhorizontalsemi-cylindrical form, one within the other, and havingdownwardlyextending sides that are joined along their lower edges toform water-legs along the sides of the fire-chamber, which is within theupwardly-arched under portion of the boiler. The objects of myinventionare toimprove the structure of the boiler and to adapt the same forpractical and economical use for highpressure heating and steamingpurposes, to increase the efficieucy and durability of boilers of theclass named, to provide a practical and efiicient means for connectingand retaining the upwardly-arched sheets in proper relation to eachother, and to provide means for retaining the foot of the arched boilerfrom spreading, and means for preventing the inner arched sheet fromcollapsing at the haunches of its arch. These objects I attain by theboiler constructed and having its parts combined in the manner set forthin the following detailed description, the particular features ofinvention and subject-matter claimed being hereinafter definitelyspecified.

In the. drawings, Figure 1 is a transverse section of my improvedsteam-boiler. Fig. 2 is a vertical longitudinal section of the same atlinear: as, Fig. 1. Fig. 3 is a section through one of theconnecting-bar joints at the bottom part of the boiler. Fig. 4 shows thedetail of the arch-crown connector. Fig. 45* shows a modification in theattachment of the arch-crown connector to the boiler-shell, and Fig. 5is a perspective view of one of the haunch-supporters.

Referring to parts, a and a indicate the under and upper sheets of theboiler A, both of which are of horizontal semi-cylindricalupwardly-arched form with downwardly-entending sides, the lesserbeingarranged within the greater and their lower horizontal edges withinthe lower arch on forms the fire-chamber F. At the bottom part of theboiler the opposite sides are connected at desired intervals of itslength by strong tie-rods O, that extend transversely across below thefire-space and have their ends secured in suitable ears b, fixed on orcast integral with the joint-bars B, said tie-rods being preferablypassed through perforations in the ears and strained up by nuts screwedonto the threaded ends against the outside of the ears I). The cars bare best made with an inward olfset or pro ecting ledge 5, (see Figs. 1and 3,) and under-channeled transom-bars D are supported in conjunctiontherewith,.which overlie the tie-rods O and serve both as guards forsaid rods and as bearers for the grate-bars G, which latter can restthereon, as shown in Figs. 1 and 3; or, if in any instance preferred,the grate-bars can be supported directly upon the tie-rods C, asindicated at the right in Fig. 2. The series' of longitudinal tubes 6,disposed above the lower arched sheet a, are arranged in groups withlateral horizontal spaces, and a central vertical space separates theseveral groups, as shown. Within the horizontal spaces I arrange aseries of transverselydisposed horizontal stay-rods f, connecting thetwo opposite sides of the upper arched sheet a at or near the springingof its arch and also at one or more intervals below the same. (See Fig.1.) Said horizontal trans verse rods are preferably disposed atintervals of from eight inches to twelve inches (more or less) apartthrough the length of the boiler. (See Fig. 2.)

WVithin the vertical space between the groups of tubes I provide thecentral hangers or crown-connectors I, whereby the under and upperarched sheets a, and a are connected to each other at intervals of, say,one foot (more or less) along the center orcrown of their arches. Theseconnectors each consist of a between the water-legs at the foot of theboiler and supported 011 the transom-barsor tie-rods,

bar having its upper end attached by a yoke 1' or angle-plates to theinner side of the sheet a, while the lower end of said bar is coupled toa yoke 1 having its respective ends riveted to the crown of the lowerarched sheet a, as indicated at 2', Fig. 1. Said crown-connector servesto support the two arches in proper relation to each other and preventthe 1nternal pressure from changing the form of the boiler-chamber byforcing the arches away from each other. The ends of the bar I can bebifurcated and attached to the yoke by a pin or bolt, as indicated inFig. 4, or in lieu thereof angles or ear-pieces can be riveted to thesheet a and the straight perforated end of the bar secured thereto, asindicated in Fig. 4; or the connection may be made inv other suitablemanner for giving equivalent attachment of the parts.

K K indicate the supporters whereby the hau'nches of the inner arch orsheet a are connected to the uprightsidesof the outer sheet a shown inFigs. 1 and 5, arranged in inclined position at intervals of eight totwelve inchesapart, their outer ends riveted at 4 to the sheet a,.andtheir inner ends riveted to the sheet or at the haunch of the arch, asat 6, so thatthe said arch cannot collapse by springing of the sheet atthe haunch. At their upright. sides the two sheets a and ct areconnectedby a series of stay-bolts 7', 8, and 9, disposed at suitableintervals and having their ends firmly secured in the respective sheetsby the usual method of fastening.

m'm indicate longitudinal stay-rods con-- necting the heads a Thegrate-barsG are disposed in the space as indicated.

In lieu of. extending the fire-grate the full- By the improvedconstruction herein shown and described I produce a boiler of thearched.

form, which can be successfully employed for high pressures, heating,and steam purposes, and which is capable of giving'hi'gh efiiciency ofservice.

Said supporters are preferably formed as It will be understood that I donot broadly.

hereinbefore specified; but my invention relates to the improvedfeatures of construction in boilers of this class, as defined.

I claim as my invention herein,to be secured by Letters Patent 1.v Thecombination, with the boiler having its shell composed of theupwardly-arched sheets a and a, with downwardly-extending sides joinedalong their lower horizontal edges j with the joint-bars B, constructedas shown,

of the transversely-disposed tie-rods'C, con- 7 necting the oppositesides of thehoiler across =thespacc beneath the fire-chamber, substan- 1tialsly as and for the purpose set forth.

2. The combination, with the boiler having its shell composed of the twoupwardly-arched sheets a and a, with downwardly-extending sides joinedattheir lower horizontal edges, of

the joint-plates B, provided with perforated ears I), havinginwardly-offset ledges 5, the

. transverse stay-rods 0, arranged through said ears and connecting thetwo opposite sides of vthe boiler, and the underchanneled transombars D,overlying said rods and supported 1 in conjunction with said offsetledgesfor sustaining the grate-bars, allsubstantially' as set forth.

3. A boiler constructed substantially as herein shown and described,comprising the upwardly-arched sheets e and a,.the= seriesoflongitudinal tubes 6 above the lower archedsheet, the transverse staysf, fixed in the sheet 1 a below its arch and passing'horizoutallybetween groups of tubes, the crown-connectors I, passing verticallybetween the tubes,- the 1 haunch-snpporters K, the side stays, and thetransverse rods 0', connecting the, opposite sides of the boilerat theirlower edges, all. of said parts being combined in the manner andi forthe purpose set forth.

Witness my hand this 15th day of February, 'A.. D. 1892.

GEORGE L. ALLEN.

Witnesses:

CHAS. H. BURLEIG-H, ELLA P. BLENUs.

